In the olden days... long before the internet... advertisers had a term for ads on the front page of a newspaper that would not be seen when the paper was on the newsstand or left on a table - below the fold.

Generally, if you were paying for a front page ad, you would pay less if your ad was to be positioned below the fold. Makes sense.

Online advertisers have borrowed this term to describe ads that are on a web page, but that are not visible to the user unless they scroll down to it.

If you are an advertiser you want your ad to be seen - obviously. And you are happy to pay for your ad to be seen. The model for this is CPM (Cost per Thousand Impressions). It differs from CPC (Cost per Click) in that you pay every time your ad appears 1,000 times on web pages. At least that's what we thought was the case.

Recent research has shown that 31% of ads are never seen. They are hidden below the fold, and the users do not scroll down to make them visible.

31% - that's 310 of your 1,000 ads - that you are paying for. 310.

And the numbers get more convoluted.... Google also report on View Through Conversions (VTC) - here's how this works. A person visits a web page with your ad on it - but doesn't click on the ad. Later, through some other source, they get to your web page and convert (complete a purchase, sign up for your newsletter - whatever you have configured as a conversion). Google allocates a VTC to the original ad impression.

But, as we have seen, 31% of these ads were never actually visible. This is equivalent to claiming the effectiveness of an ad that was in a magazine on the dentist's waiting room table. You didn't read the magazine - or even touch it - but the ad was there and you could have done. In this context the whole thing sounds pretty far fetched.

Google are fixing things. They are rolling out Active View CPM - where impressions will only count if they are actually viewed.

At present this is an option that advertisers must select, but the plan is for this to become standard across all accounts.

Select your GDN campaign and click on the Display Network tab.

Then scroll down to the bottom of the page where you will find the exclusions (this will be for keywords, or placements depending upon the view you have selected). Under Ad Location - exclude Below the Fold and save.

This will now ensure that your ads will only appear when a user opens up a web page - if your ad cannot appear in the opening window, then it will not appear at all and you will not be paying for 310 impressions in every 1,000.

This may lead to an increase in your CPM - though it should not be a significant increase, but most would agree that it is better to get what you pay for.